Glass ampules which are used as containers for pharmaceuticals are generally provided with a score line which is located on the constricted portion of the ampule. The ampule is broken at the constriction in order to remove its contents. The presence of the score line facilitates a smooth break, and the absence of a score line (or the presence of a score line which does not extend completely around the circumference of the constriction) may result in jagged edges or splinters when the ampule is broken. In order to insure the presence of a complete score line, inspection of the ampule is necessary. Previously this has been accomplished by visual inspection. Problems associated with visual inspection are those of speed and accuracy.
Several systems have utilized laser beams for the inspection of glass containers. In U.S. Pat. No. 3,302,786 a laser beam is utilized to inspect the rim of a glass container. However, detection of defects is accomplished by sensing a redirection of the laser beam when it strikes a defect, rather than the detection of diffuse versus specular reflection. In U.S. Pat. No. 3,684,385, measurement of the diminution in intensity of a laser beam as it passes through a translucent material is utilized to detect defects in the material. This is likewise not related to the type of reflection which occurs when the laser beam strikes the container surface.
Other optical inspection devices have generally utilized a redirection of a light beam to detect defects in glass containers. Examples of this are U.S. Pat. Nos. 3,880,650 (which is utilized to inspect the sealing surface of a container), 3,887,285 (which detects reflections from checks in glass containers), and 3,639,067 (which uses a fiber optic device to detect checks). These patents do not involve either the use of a laser beam or the detection of diffuse versus specularly reflected light.